Guide for assisting with arrangement of a stock instrument with respect to a patient tissue

ABSTRACT

A stock instrument includes at least one guide interacting feature. A lower instrument surface of the stock instrument is placed into contact with the patient tissue. A guide has a lower guide surface contoured to substantially mate with at least a portion of an upper instrument surface of the stock instrument. A predetermined instrument orientation upon the patient tissue is defined, which is preselected responsive to preoperative imaging of the patient tissue. The guide and instrument are mated in a predetermined relative guide/instrument orientation wherein at least one guide interacting feature of the instrument is placed into engagement with at least one instrument guiding feature of the guide. The guide is moved into a predetermined guide orientation with respect to the patient tissue and concurrently the instrument is moved into a predetermined instrument orientation with respect to the patient tissue.

RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/282,528 filed Oct. 27, 2011, which claims priority from U.S.Provisional Application No. 61/408,376 filed Oct. 29, 2010, the subjectmatter of each of which is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

The present invention relates to a system and method for use of asurgical guide and, more particularly, to a system and method for use ofa surgical guide for assisting with arrangement of a stock instrumentwith respect to a patient tissue.

BACKGROUND OF THE INVENTION

The efficient functioning of the shoulder joints is important to thewell-being and mobility of the human body. Each shoulder joint includesthe upper portion of the humerus, which terminates in an offset bonyneck surmounted by a ball-headed portion known as the humeral head. Thehumeral head rotates within a socket, known as the glenoid fossa, in thescapula to complete the shoulder joint. Diseases such as rheumatoid- andosteo-arthritis can cause erosion of the cartilage lining of the glenoidfossa so that the ball of the humerus and the scapula rub together,causing pain and further erosion. Bone erosion may cause the bonesthemselves to attempt to compensate for the erosion which may result inthe bone becoming deformed. This misshapen joint may cause pain and mayeventually cease to function altogether.

Operations to replace the shoulder joint with an artificial implant arewell-known and widely practiced. Generally, the shoulder prosthesis willbe formed of two components, namely: a glenoid, or socket, componentwhich lines the glenoid fossa, and a humeral, or stem, component whichincludes a weight-bearing ball and replaces the humeral head. (Each ofthese components may be made up of multiple subassemblies.) Alternately,a reverse shoulder prosthesis has a ball as the glenoid component and asocket as the humeral component, but the following description presumesa standard, not reverse, shoulder prosthesis arrangement. During thesurgical procedure for implanting the shoulder prosthesis, the remainingcartilage or damaged tissue is removed from the glenoid fossa using areamer such that the native glenoid fossa will accommodate the outersurface of the glenoid component of the shoulder prosthesis. The glenoidcomponent of the prosthesis can then be inserted into the preparedglenoid fossa. Generally, fixing means such as screws and/or bone cementmay be used to hold the glenoid component in the glenoid fossa. There isalso generally an implant stem provided to the glenoid implant, the stembeing inserted into a prepared cavity in the glenoid fossa to anchor theglenoid implant. The use of additional fixing means and anchor(s) helpsto provide stability after the prosthesis has been inserted. In somemodern prosthesis, the glenoid component may be coated on its externalsurface with a bone growth promoting substance which will encourage boneingrowth which also helps to hold the glenoid component in place. Thehumeral head also is removed during the surgical procedure, and thehumerus shaft hollowed out using reamers and rasps to accept the humeralcomponent of the prosthesis. The stem portion of the prosthesis isinserted into the humerus and secured therein to complete the shoulderjoint replacement.

In order to strive toward desired performance of the combined glenoidand humeral shoulder prosthesis components, the glenoid portion shouldbe properly positioned upon the glenoid fossa (among otherconsiderations). The glenoid portion positioning is particularlyimportant since incorrect positioning of the glenoid component can leadto the prosthetic shoulder joint suffering from dislocations, adecreased range of motion, and possibly eventual loosening and/orfailure of one or both components of the joint.

Generally, the normal glenoid retroversion of a given patient may fallwithin a range of approximately 20° (5° of anteversion and 15° ofretroversion). (The version of the glenoid is defined as the anglebetween the plane of the glenoid fossa to the plane of the scapulabody.) In the pathologic state, glenoid bone loss may result in a muchlarger range of version angles.

One goal of shoulder surgery may be to modify the pathologic bone tocorrect pathologic version to be within the normal range or the normalversion of the patient's native anatomy before the bone loss occurred.During surgery, and particularly minimally invasive procedures, theplane of the scapula may be difficult or impossible to determine bydirect visual inspection, resulting in the need for assistive devices ormethods to define both the pathologic version present at the time ofsurgery and the intended correction angle.

It is generally believed that there is a preferred orientation for theglenoid component to provide a full range of motion and to minimize therisk of dislocation or other mechanical component failure. Some exampleorientations of the glenoid prosthesis relative to the glenoid face areabout 5° of anteversion to about 15° of retroversion; average version isabout 1-2° of retroversion. This broadly replicates the natural angle ofthe glenoid. However, the specific angular orientation of the glenoidportion varies from patient to patient.

With a view to overcoming these disadvantages, some arrangements havebeen recently suggested in which a three-dimensional intraoperativecomputer imaging surgical navigation system is used to render a model ofthe patient's bone structure. This model is displayed on a computerscreen and the user is provided with intraoperative three-dimensionalinformation as to the desired positioning of the instruments and theglenoid component (or any component, depending on the subject patienttissue) of the prosthetic implant. However, surgical navigationarrangements of this type are not wholly satisfactory since theygenerally use only a low number of measured landmark points to registerthe patient's anatomy and to specify the angle of the prosthetic implantcomponent (e.g., a glenoid component), which may not provide the desiredlevel of accuracy. Further, the information provided by such systems maybe difficult to interpret and may even provide the user with a falsesense of security. Moreover, these systems are generally expensive toinstall and operate and also have high user training costs. Variousproposals for trial prosthetic joint components and assistiveinstruments have been made in an attempt to overcome the problemsassociated with accurately locating the glenoid portion of theprosthetic implant. While these trial systems and instruments may helpwith checking whether the selected position is correct, they are notwell-suited to specify the correct position initially, and thus therestill is user desire for a system which may assist a user in placementof prosthetic implant component in a prepared native tissue site.

SUMMARY OF THE INVENTION

In an embodiment of the present invention, a method of arranging a stockinstrument with respect to a patient tissue is described. The stockinstrument includes at least one guide interacting feature. A lowerinstrument surface of the stock instrument is placed into contact withthe patient tissue. A guide having a lower guide surface contoured tosubstantially mate with at least a portion of an upper instrumentsurface of the stock instrument, an upper guide surface spacedlongitudinally apart from the lower guide surface by a guide body, andat least one instrument guiding feature at a predetermined featurelocation with respect to the guide body is provided. A predeterminedinstrument orientation upon the patient tissue is defined. Thepredetermined instrument orientation is preselected responsive topreoperative imaging of the patient tissue. The lower guide surface isplaced into mating contact with at least a portion of the upperinstrument surface in a predetermined relative guide/instrumentorientation wherein at least one guide interacting feature of theinstrument is placed into engagement with at least one instrumentguiding feature of the guide. The guide is moved into a predeterminedguide orientation with respect to the patient tissue and concurrentlythe instrument is moved into a predetermined instrument orientation withrespect to the patient tissue.

In an embodiment of the present invention, a guide for assisting witharrangement of a stock instrument with respect to a patient tissue isdescribed. A lower guide surface is configured to contact an upperinstrument surface of the stock instrument when a lower instrumentsurface of the stock instrument is in contact with the patient tissue.The lower guide surface is contoured to substantially mate with at leasta portion of the upper instrument surface. An upper guide surface isspaced longitudinally apart from the lower guide surface by a guidebody. The upper guide surface is accessible to a user when the lowerguide surface is in contact with the upper instrument surface. Anorienting feature is configured to enter a predetermined orientingrelationship with a previously placed landmark while the lower guidesurface is in mating contact with at least a portion of the upperinstrument surface in a predetermined relative guide/instrumentorientation. The predetermined orienting relationship indicates that theinstrument has achieved a predetermined instrument relationship with thepatient tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference may be made tothe accompanying drawings, in which:

FIG. 1 is a perspective top view of an example use environment;

FIG. 2 is a perspective bottom view of a first prior art prostheticcomponent;

FIG. 3 is a perspective bottom view of a first prior art instrument foruse with the component of FIG. 2;

FIG. 4 is a top view of the instrument of FIG. 3;

FIG. 5 is a perspective bottom view of an embodiment of the presentinvention;

FIG. 6 is a top view of the embodiment of FIG. 5;

FIG. 7 is a top view of the embodiment of FIG. 5 and the instrument ofFIG. 3 in the example use environment of FIG. 1;

FIG. 8 is a top view of a second prior art instrument for use with thecomponent of FIG. 2 or a similar component;

FIG. 9 is a perspective bottom view of the instrument of FIG. 8;

FIG. 10 is a top view of an embodiment of the present invention;

FIG. 11 is a bottom view of the embodiment of FIG. 10; and

FIG. 12 is a top view of the embodiment of FIG. 10 and the instrument ofFIG. 8 in the example use environment of FIG. 1.

DESCRIPTION OF EMBODIMENTS

FIG. 1 depicts a portion of the external surface of a (left) scapula100, which is an example of a possible patient tissue use environmentfor the described systems, apparatuses, and methods, with particularemphasis on the glenoid fossa 102. Directional arrow 104 indicates thesuperior/inferior and anterior/posterior directions. A glenoid implant206, shown in FIG. 2, is the stock prosthetic implant for use with aprosthetic shoulder replacement surgery for the described embodiments ofthe present invention. The glenoid implant 206 includes an implant shaft208, a lower implant surface 210, an upper implant surface 212 (hiddenin this view, as shown via dashed line), and a plurality of fasteningpegs 214 extending from the lower implant surface. The patient tissue isshown and described herein at least as a scapula and the prostheticimplant component is shown and described herein at least as an glenoidprosthetic shoulder component, but the patient tissue and correspondingprosthetic implant component could be any desired types such as, but notlimited to, hip joints, shoulder joints, knee joints, ankle joints,phalangeal joints, metatarsal joints, spinal structures, long bones(e.g., fracture sites), or any other suitable patient tissue useenvironment for the present invention. For example, the prostheticimplant component could be an internal fixation device (e.g., a boneplate), a structure of a replacement/prosthetic joint, or any othersuitable artificial device to replace or augment a missing or impairedpart of the body.

The term “lateral” is used herein to refer to a direction indicated bydirectional arrow 104 in FIG. 1; the lateral direction in FIG. 1 liessubstantially within the plane of the drawing and includes all of thesuperior, inferior, anterior, and posterior directions. The term“longitudinal” is used herein to refer to a direction definedperpendicular to the plane created by directional arrow 104, with thelongitudinal direction being substantially into and out of the plane ofthe drawing in FIG. 1 and representing the proximal (toward the medialline of the body) and distal (out from the body) directions,respectively.

During installation of the glenoid implant 206, a shaft aperture (notshown) is drilled into the patient tissue (here, the patient's glenoidfossa 102) at a predetermined location and a stock instrument is used tohelp prepare the patient tissue surface. The stock instrument isdepicted here as a glenoid instrument 316 according to a firstembodiment of the present invention, shown in FIG. 3. Suitableinstruments 316 similar to those shown herein are available from DePuyOrthopaedics, Inc., of Warsaw, Ind. The instrument 316 includes aninstrument shaft 318, a lower instrument surface 320, an upperinstrument surface 322 (hidden in this view, as shown via dashed line),and at least one guide interacting feature 324.

The term “stock” is used herein to indicate that the component indicatedis not custom-manufactured or -configured for the patient, but isinstead provided as a standard inventory item by a manufacturer. Aparticular stock component may be selected by the user from a productline range of available components, with the user specifying a desiredconfiguration, general or particular size (e.g., small, medium, large ora specific measurement), material, or any other characteristic of thecomponent. Indeed, the stock component could be manufactured only afterthe user has selected the desired options from the range of choicesavailable. However, the stock component is differentiated from acustom-manufactured or bespoke component in that the stock component isagnostic and indifferent regarding a particular patient anatomy duringthe design and manufacturing processes for an implant intended for thatpatient, while the patient anatomy is an input into at least one designand/or manufacturing process for a custom-manufactured component. Thefollowing description presumes the use of a stock instrument, though oneof ordinary skill in the art will be able to provide for the use of thepresent invention with a custom-manufactured instrument, instead.

At least one of the guide interacting features 324 may bear a directpositional relationship to some feature of the glenoid implant 206.Here, the guide interacting features 324 are located analogously to thefastening pegs 214 of the glenoid implant 206 and may later assist inguiding some aspect of patient tissue modification to ready the glenoidfossa 102 for the glenoid implant 206 in a known manner and as will bediscussed in further detail below.

As can be seen in FIG. 4, the instrument 316 according to the firstembodiment of the present invention may include at least one handlingfeature 426 to accept a handle (not shown) which the user may manipulateto move the instrument at or near the surgical site—two throughholehandling features and one closed (blind) cavity handling feature areshown in the Figures. The instrument 316 may also include one or moresecuring features 428 for assisting with holding the instrument 316 in apredetermined instrument with the patient tissue, if desired.

During installation of the glenoid implant 206, it is known for a userto place a stock instrument 316 on the patient tissue to help guidesurgical tools used to prepare the patient tissue to receive the glenoidimplant. For example, a central shaft aperture (which will later receivethe implant shaft 218) can be machined at a desired location on theglenoid fossa 102, and the instrument shaft 318 can be placed into theshaft aperture to help hold the instrument 316 in place while theinstrument is used as a template for the user to drill, ream, cut,scrape, graft, or otherwise modify the patient tissue from a native orpathologic state to accept the glenoid implant 206 as desired accordingto the preoperative plan and/or an intraoperative decision.

The shaft aperture can be located on the glenoid fossa 102 by the userwith relatively little difficulty, such as with the assistance of alandmark (not shown), such as a guide pin, wire, marking, and/or otherlocation indicator previously placed in a predetermined relationshipwith the patient tissue. The landmark may be any suitable two- orthree-dimensional landmark such as, but not limited to, a native oracquired anatomical feature of the patient tissue and/or a separatelyprovided landmark placed with the assistance of a guide as disclosed inco-pending U.S. patent application No. to be determined, filed Oct. 27,2011, titled “System and Method for Association of a Guiding Aid with aPatient Tissue” and claiming priority to U.S. Provisional PatentApplication No. 61/408,359, filed Oct. 29, 2010 and titled “System andMethod for Association of a Guiding Aid with a Patient Tissue”, theentire contents of both of which are incorporated herein by reference.The landmark could also or instead be placed using a robotic surgicalaid, adjustable reusable (e.g., “dial-in”) tools, intraoperativeimaging, or any other suitable placement aid. Optionally, an originallandmark could have been previously placed, then removed for any reason(e.g., to facilitate machining of the glenoid fossa 102 surface). Asecond landmark may then be placed at the same location and with thesame location as the original landmark, such as via reusing the cavityin the surface left by the removal of the original landmark. Indeed, theremaining cavity in the surface itself may serve a landmarking function.Through these or any other such transformations of physicalmanifestations, the position information represented by the originallandmark and preoperatively planned may be preserved and used duringvarious stages of the surgical procedure regardless of the way in whichthat position landmark is made available to the user at those variousstages.

Once the shaft aperture is located as desired and the instrument shaft318 is inserted to substantially place the lower instrument surface 320in contact with the patient tissue of the glenoid fossa 102, however,the instrument 316 may still be in an orientation that does not comportwith a preoperatively planned positioning. Once the instrument shaft 318is located inside the shaft aperture, the instrument 316 can pivot aboutan axis provided by the instrument shaft. For precision in pivoting theinstrument into a desired rotational orientation with respect to theglenoid fossa 102, the user may choose to employ a guide 530, such asthat shown in FIGS. 5-7.

With reference to FIGS. 5-6, a guide 530 has a lower guide surface 532configured to contact an upper instrument surface 322 of the instrument316 when a lower instrument surface 320 of the instrument is in contactwith the glenoid fossa 102. The lower guide surface 532 is contoured tosubstantially mate with at least a portion of the upper instrumentsurface 322, as will be discussed below. The term “mate” is used hereinto indicate a relationship in which the contours of two structures areat least partially matched or coordinated in at least two dimensions.For example, both the lower guide surface 532 and the upper instrumentsurface 322 could have profiles that are concavely curved, convexlycurved, planar/linear, or any combination of those or other profileshapes. The guide 530 also includes an upper guide surface 634 spacedlongitudinally apart from the lower guide surface 532 by a guide body536. The upper guide surface 634 is accessible to a user when the lowerguide surface 532 is in contact with the upper instrument surface 322.

The patient's name, identification number, surgeon's name, and/or anyother desired identifier may be molded into, printed on, attached to, orotherwise associated with the guide 530 in a legible manner. The guide530 may be made by any suitable method such as, but not limited to,selective laser sintering (“SLS”), fused deposition modeling (“FDM”),stereolithography (“SLA”), laminated object manufacturing (“LOM”),electron beam melting (“EBM”), 3-dimensional printing (“3DP”), contourmilling from a suitable material, computer numeric control (“CNC”),other rapid prototyping methods, or any other desired manufacturingprocess.

The guide 530 may include at least one instrument guiding feature 538 ata predetermined feature location with respect to the guide body 536. Atleast one guide interacting feature 324 of the instrument 316 may beconfigured for engagement with at least one instrument guiding feature538 of the guide 530. As shown in FIG. 5, each instrument guidingfeature 538 is a protrusion from the lower guide surface 532 and eachguide interaction feature 324 is a cavity, and the protrusion enters thecavity to engage the guide 530 and the instrument 316 in the matingcontact in the predetermined relative guide/instrument orientation.However, one of ordinary skill in the art could readily reverse thatcavity/protrusion status for one or more guide interacting features 324and/or instrument guiding features 538, or could provide differentmechanical structures (i.e., other than a cavity or protrusion) to carryout the described engagement.

As can be seen in FIG. 5, the lower guide surface 532 includes ahexagon-shaped protruding instrument guiding feature 538, which may beconfigured to engage with a correspondingly located and complementarilyshaped handling feature 426 of the instrument 316 to supplement orsupplant the engagement of the round instrument guiding features intransferring motive force between the guide 530 and the instrument 316.It is contemplated that engagement between one or more guide interactingfeatures 324 and instrument guiding features 538 will assist the userwith concurrently moving one of the guide 530 and the instrument 316 viaa motive force exerted on the other of the guide and the instrument.Alternately, the user may directly grasp and move both the guide 530 andthe instrument 316 at once—in this situation, the engagement between theguide interacting features 324 and instrument guiding features 538 maysimply assist with maintaining the guide and the instrument in thepredetermined relative guide/instrument orientation. Here, the hexagonalinstrument guiding feature 538 is collinear with the handling feature426, which is collinear with the instrument shaft 318. Because theinstrument shaft 318 may interact with a shaft aperture in the patienttissue serving as a landmark, the hexagonal instrument guiding feature538 could be considered to be an extension or indication of the positionof the landmark, as well. The hexagonal edges of the centrally locatedinstrument guiding feature 538 may also be helpful in interacting withthe hexagonal handling feature 426 of the instrument 316 to “grip” andtransmit force (especially rotational force) between the guide 530 andthe instrument in a way that the other, substantially cylindricalguiding features shown in FIG. 5 might not be able to accomplish.

As depicted in FIG. 6, the guide 530 may include a handling feature 426which can be used with a handling tool (not shown) similarly to, andpotentially in combination with, the handling features 426 of theinstrument 316. Sometimes the available maneuvering space in a surgicalfield is relatively restricted, and it may be useful for a forceps, hexwrench (perhaps with a frictional fit or other feature to nest into thehandling feature 426), Kocher tool, hemostat, or other user-manipulatedhandling tool (not shown) to selectively interact with the handlingfeature to hold the guide 520 or instrument 316 steady and/or to movethe guide or instrument to a desired position. One or more features,such as indents, apertures, cavities, lugs, undercuts, or any othersuitable structures could be provided to the handling feature 426 or toany other structure of the guide 530 or instrument 316 to facilitategripping of the guide by any handling tool, in general, and/or by aparticular handling tool.

An orienting feature 540, such as the depicted extension in FIGS. 5-7,may be provided to the guide 530. As shown here, for use with theinstrument 316 in a glenoid implant 206 surgical procedure, theorienting feature 540 may extend, perhaps substantially, longitudinallyand/or laterally from the guide 530, but the direction, amount, and typeof extension will depend upon the location and type of body tissue withwhich the guide 530 is being used. The orienting feature 540 may beconfigured to enter a predetermined orienting relationship with alandmark (not shown), such as a guide pin, wire, marking, and/or otherlocation indicator previously placed in a predetermined relationshipwith the patient tissue, such predetermined orienting relationshipoccurring when the lower guide surface 532 is in mating contact with atleast a portion of the upper instrument surface 322 in a predeterminedrelative guide/instrument orientation. The achievement of thepredetermined orienting relationship indicates that the instrument 316has achieved a predetermined instrument relationship with the patienttissue. (The predetermined relative guide/instrument orientation isachieved when the guide 530 and instrument 316 are mated in a desiredmanner, as predetermined via preoperative imaging and/or analysis.)

The landmark for use with the orienting feature 540, similarly to anylandmark used to help locate the shaft aperture as described above, maybe any suitable two- or three-dimensional landmark and placed in anydesired manner. It may be helpful for the landmark for use with theorienting feature 540 to be affixed to the patient tissue at a locationspaced from a location of the stock instrument 530.

Optionally, the orienting feature 540 may include an orienting indicator542. When present, the orienting indicator 542 may be configured toachieve a predetermined signaling relationship (the signalingrelationship being directly related to the orienting relationship) withthe landmark, as will be described below, while the guide 530 and theinstrument 316 are in the predetermined relative guide/instrumentorientation. For example, in the first embodiment shown in FIGS. 5-7,the orienting feature 540 is a arm-type structure extending from theguide body 536 and the orienting indicator 542 is a notch in theorienting feature 540 shaped to somewhat closely surround at least aportion of the diameter of a guide pin or other three-dimensionallandmark to achieve the predetermined signaling relationship. Thelandmark(s) were previously placed in any suitable manner inpredetermined locations at the surgical site. Accordingly, thepredetermined signaling relationship between the landmark(s) and theorienting indicator(s) 542 assists the user in placing the guide 530into a predetermined guide orientation with respect to the patienttissue.

When the guide 530 and the instrument 316 are held in a predeterminedrelative guide/instrument orientation (e.g., through the use of theguide interacting feature 324 and instrument guiding feature 538,frictional engagement between the upper instrument surface 322 and lowerguide surface 532, any other mechanical linkage, or even merelycoordinated movement of each by the user), then the instrument ismanipulated in concert with the guide. Accordingly, movement of theguide 530 into the predetermined guide orientation—as signaled bycoordination of the landmark(s) and the orienting feature 540—willconcurrently move the instrument 316 into a predetermined instrumentorientation with respect to the patient tissue. One of ordinary skill inthe art can readily preoperatively plan the placement and type oflandmark(s), as well as the structure and type of orienting feature(s)540 and/or orienting indicator(s) 542 to assist the user in guiding theinstrument 316 into the predetermined instrument orientation and/orlocation with respect to the patient tissue for a particular applicationof the present invention.

While the orienting indicator 542 is shown in FIGS. 5-7 as being anotch, any suitable structure, notch-like or otherwise, could be used asan orienting indicator. For example, the orienting indicator 542 couldbe a lug extending from the orienting feature 540, a visual indicatorsuch as a line drawn or etched on the orienting protrusion, or even amechanical system such as a latch or trip-wire.

Much of the success of a prosthetic joint replacement arises from secureaffixation of the glenoid implant 206 to the scapula 100, and anchoringof the fastening pegs 214 into robust bony matter contributes to asuitably snug fit between the glenoid implant and the scapula. However,pathological anatomy of the scapula 100 may affect where the fasteningpegs 214 can be securely placed. The native and pathological anatomiesdiffer from patient to patient, so preoperative patient imaging scansmay be used to preoperatively plan desired locations and trajectoriesfor the fastening pegs 214 to be inserted into the scapula 100. However,and particularly during minimally invasive surgeries, very little of thescapula 100 may be visible to the user, and the visible portion of thescapula may be located at the distal end of a “tunnel” of surroundingsoft tissue temporarily retracted by the user—accordingly, availablemaneuvering space at the surgical site may be severely restricted. Inaddition, the patient's shoulder may be actually canted slightlydifferently during the surgical procedure than planned preoperatively.These are among the factors which may result in a preoperative plan fora particular glenoid implant 206 installation being very difficult andtime-consuming for a user to actually perform in an operativeenvironment.

To aid with carrying out a preoperative plan for attaching a stockprosthetic implant to a patient tissue, the guide 530 may bepreoperatively generated. The guide 530 is at least partiallycustom-manufactured for a particular patient responsive to preoperativeimaging of the patient tissue. For example, the guide 530 may be whollycustom-made (e.g., using rapid prototyping techniques) or may bemodified from a stock guide or guide blank (not shown). It iscontemplated that at least a part of the guide 530 is apatient-specific, single-use, bespoke feature suited only for use at theindicated surgical site. For example, a stock guide body 536 (e.g., they-shaped portion of the structure in FIGS. 5-6) could be supplementedwith a patient-specific orienting feature 540 (e.g., the protruding,asymmetrical arm structure in FIGS. 5-6). One of ordinary skill in theart could create a guide which uses a patient-specific “disposable”structure connected to a stock, generic “reusable” carrier in thismanner, with any desired attachment mechanism connecting the two in asufficiently rigid portion to carry out the interactions discussedherein.

Regardless of the whole/partial custom manufacture status, the guide 530may be configured responsive to at least one of preoperative imaging ofthe patient tissue and preoperative selection of the stock prostheticimplant. Because the instruments 316 are stock items, related tospecific stock prosthetic implants (e.g., the depicted glenoid implants206), the guide 530 also may be at least partially a stock item. Theorientation of the instrument 316 upon the glenoid fossa 102 ispredetermined by a user before the guide 530 is provided. Thispredetermination may occur intraoperatively, as the user is able todirectly see the condition of the surgical site. However, it iscontemplated that a predetermination of the desired instrumentorientation could be accomplished preoperatively, with reference topreoperative imaging of the patient tissue. In this manner, a user cancreate a patient tissue model for observation, manipulation, rehearsal,or any other pre-operative tasks. The term “model” is used herein toindicate a replica or copy of a physical item, at any relative scale andrepresented in any medium, physical or virtual. The patient tissue modelmay be a total or partial model of a subject patient tissue, and may becreated in any suitable manner. For example, and as presumed in thebelow description, the patient tissue model may be based upon computertomography (“CT”) data imported into a computer aided drafting (“CAD”)system. Additionally or alternatively, the patient tissue model may bebased upon digital or analog radiography, magnetic resonance imaging, orany other suitable imaging means. The patient tissue model willgenerally be displayed for the user to review and manipulatepreoperatively, such as through the use of a computer or other graphicalworkstation interface.

During preoperative planning, the user can view the patient tissue modeland, based upon knowledge of other patient characteristics (such as, butnot limited to, height, weight, age, and activity level), then choose adesired stock prosthetic implant. Because three-dimensional image modelsare available of many stock prosthetic implants, the user may be able to“install” the stock prosthetic implant virtually in the patient tissuemodel via a preoperative computer simulation. During such a simulation,the user can adjust the position of the stock prosthetic implant withrespect to the patient tissue, even to the extent of simulating thedynamic interaction between the two, to refine the selection, placement,and orientation of the stock prosthetic implant for a desired patientoutcome. For example, a system similar to that of co-pending U.S. patentapplication No. to be determined, filed Oct. 26, 2011, titled “System ofPreoperative Planning and Provision of Patient-Specific Surgical Aids”and claiming priority to U.S. Provisional Patent Application No.61/408,392, filed Oct. 29, 2010 and titled “System of PreoperativePlanning and Provision of Patient-Specific Surgical Aids”, the entirecontents of both of which are incorporated herein by reference, or anysuitable preoperative planning system could be used.

Once a chosen stock prosthetic implant has been virtually placed in adesired position and orientation with respect to the patient tissue, theorientation of the implant, and thus of the instrument 316, can also beplanned through the use of the computer simulation, with considerationof the location, amount, and pathology of the patient tissue being takeninto account in instrument selection and placement planning. By handand/or with automatic computer assistance, the user can experiment withvarious sizes, placements, and orientations for an instrument that canbe used to help achieve the desired patient tissue remodeling. Forexample, the selected instrument 316 may contain at least one patienttissue modification feature (e.g., a reaming window, drill guideaperture, or any other structure which can help a user in placing and/orconducting some patient tissue modification), which indicates apredetermined location for a patient tissue modification procedure whenthe instrument is in the predetermined instrument orientation withrespect to the patient tissue. In this manner, the final desiredlocation of the fastening pegs 214 in the patient tissue, or any otherpatient tissue modification desired, may be used to work backward anddetermine selection of a suitable instrument 316 and from there to apredetermined instrument orientation on the glenoid fossa 102, both interms of lateral positioning and rotational orientation.

When the instrument 316 positioning and selection has been finalized ina virtual manner, the guide 530 can be generated, and landmark(s) forinteraction with the orienting feature 540 virtually placed with respectto the virtual instrument and the virtual patient tissue. The user maythen have the opportunity to adjust the virtual guide 530 before aphysical guide 530 is produced. (Hereafter, in the description of thefirst embodiment, the guide 530 is presumed to be physical.)

In FIG. 7, a scapula 100 is shown in an intraoperative arrangement.Here, the instrument 316 has been placed atop the glenoid fossa 102 withthe instrument shaft 318 received into a shaft aperture. A landmark 744has been placed at a predetermined landmark location chosen responsiveto preoperative imaging of the patient tissue. Here, the landmark 744 isspaced from a location of the instrument 316.

The lower guide surface 532 of the guide 530 has been mated with aportion of the upper instrument surface 322 of the instrument 316 toplace the instrument and guide into the predetermined relativeguide/instrument orientation. The guide 530 and instrument 316 have thenbeen concurrently moved (either both directly or by virtue of theinteraction between some structure of the guide and a contactingstructure of the instrument) to place the guide in the predeterminedguide orientation with respect to the patient tissue, which means, sincethe guide and instrument are mated, that the instrument has achieved thepredetermined instrument orientation with respect to the patient tissue.The user knows that the predetermined guide and instrument orientationshave been achieved because the mated guide 530 and instrument 316 havebeen repositioned (here, rotated about the instrument shaft 318pivotally held in the shaft aperture) to bring the orienting feature 540into the predetermined orienting relationship with the landmark 744.More specifically in the depicted example of the Figures, since theorienting indicator 542 is a notch, the instrument 316 and mated guide530 have been repositioned such that the landmark 744 is received intothe orienting indicator 542. As an alternative to this agnosticplacement of the guide 426 and nested/attached stock prosthetic implantat the surgical site and subsequent rotation into position, the guide530 and the instrument 316 could be concurrently placed into contactwith at least one landmark (which could include the central landmark) ata location spaced apart from the patient tissue at the surgical site.For example, a landmark could be an elongate guide pin (such as thatshown in FIG. 7), and a notchlike orienting indicator 542 could beplaced into the signaling relationship with a protruding end of theguide pin some distance from the patient tissue. In this optionalsituation, the stock instrument would be guided into the predeterminedinstrument orientation concurrently with being brought into contact withthe patient tissue as the orienting indicator 542 slides along thelength of the guide pin via a rail-like dynamic guiding technique.

Regardless of how the goal of placing the instrument 316 into thepredetermined instrument orientation with respect to the patient tissue(glenoid fossa 102, here) is accomplished, the user may remove the guide530, and optionally the landmark 744, from the surgical site andcontinue with the surgical procedure using the positioned instrument asdesired once the predetermined instrument orientation has been achievedas shown in FIG. 7.

Optionally, the instrument 316 may be temporarily secured in thepredetermined instrument orientation to avoid shifting or movement ofthe instrument upon the patient tissue. For example, guide pins (notshown) could be inserted through the securing features 428 to hold theinstrument 316 in place for as long as desired by the user. Whether anadditional structure is provided or the user merely holds the instrument316 in place by hand, however, the desired patient tissue modificationsare made, the instrument 316 is removed from the patient tissue, and thesurgical procedure proceeds apace. This may include the insertion of oneor more surgical tools through at least one guide interacting structure324 of the instrument 316, since some of the guide interactingstructures additionally function as drill guides for preparation of thepatient tissue to receive the fastening pegs 214 of the glenoid implant206 here.

FIGS. 8-12 depict a guide 530′ according to a second embodiment of thepresent invention and related structures. The guide 530′ of FIGS. 8-12is similar to the guide 530 of FIGS. 5-7 and therefore, structures ofFIGS. 8-12 that are the same as or similar to those described withreference to FIGS. 1-7 have the same reference numbers with the additionof a “prime” mark. Description of common elements and operation similarto those in the previously described first embodiment will not berepeated with respect to the second embodiment.

FIGS. 8-9 depict an instrument 316′ which can be used to guide reamingor other relatively large-area patient tissue modification (as opposedto the relatively confined fastening peg 214 drilling guided by thefirst embodiment). To that end, the instrument 316′ includes arelatively large guide interacting feature 324′. For example, theinstrument 316′ of FIG. 8 could be used with the glenoid implant 206 ofFIG. 2 or with any other suitable glenoid implant (e.g., a known type ofimplant having a stepped lower implant surface, for which an area of theglenoid fossa 102′ will need to be reamed away).

Additionally, the instrument 316′ of the second embodiment does not havean instrument shaft 318, but instead has a locating aperture 846 whichaccepts a three-dimensional landmark (not shown) to position theinstrument 316′ laterally upon the glenoid fossa 102 as desired. Thelandmark which enters the locating aperture 846 could be a guidewire(not shown), such as that disclosed in co-pending U.S. patentapplication Ser. No. 13/178,324, filed Jul. 7, 2011, titled “Method andApparatus for Providing a Relative Location Indication During a SurgicalProcedure” and claiming priority to U.S. Provisional Patent ApplicationSer. No. 61/362,722, filed Jul. 9, 2010, and titled “Method andApparatus for Providing a Relative Location Indication During a SurgicalProcedure”, the contents of both of which are hereby incorporated byreference in their entirety. The landmark (not shown) received by thelocating aperture 846 may have been previously placed to provide a“pivot point” about which the instrument 316′ can rotate during guidedmovement as discussed below. This landmarking/pivot-guiding function isprovided instead by indirect action of the instrument shaft 318 in thefirst embodiment of the present invention, as previously discussed.

The lower instrument surface 320′ of the instrument 316′ of the secondembodiment also includes a plurality of holding teeth 948 which can beselectively pushed down into the patient tissue to resistrotation/pivoting of the instrument about the landmark within thelocating aperture 846.

A guide 530′ according to the second embodiment of the present inventionis shown in FIGS. 10-11. Like the instrument 316′, the guide 530′includes a locating aperture 846. The guide 530′ may include one or morehandling features 426′ (two shown), which may be configured to accept ahandling tool (not shown) or otherwise to assist the user in moving theguide at or near the surgical site.

In use, the guide 530′ of the second embodiment operates similarly tothe guide 530 of the first embodiment, as is shown in FIG. 12. Theinstrument 316′ of FIGS. 10-11 is placed upon the glenoid fossa 102surface. Optionally, a landmark (not shown) may have been previouslyplaced in the glenoid fossa 102 surface—if so, the locating aperture 846receives the landmark as a part of placing the lower instrument surface320′ in contact with the patient tissue. The guide 530′ is placed atopthe instrument 316′ with the lower guide surface 532′ in contact withthe upper instrument surface 322′. When present, the instrument guidingfeatures 538′ of the guide 530′ may mate with the guide interactingfeatures 324′ of the instrument 316′.

Once the instrument 316′ and guide 530′ are mated together in thepredetermined relative guide/instrument orientation atop the glenoidfossa 102′ surface, the instrument and guide can be moved concurrentlyto move both the guide and the instrument into predetermined guide andinstrument orientations with respect to the patient tissue. In otherwords, engagement between the guide 530′ and the instrument 316′ causesforces exerted upon the guide to be transferred to the instrument, andthe user can move both the instrument and the guide concurrently eitherby moving just the guide, or by moving both the guide and instrumentdirectly. For example, and presuming that the instrument 316′ includes alocating aperture 846 which accepts a landmark (not shown) placed in theglenoid fossa 102′ surface, a counterclockwise force (indicated bycounterclockwise arrow 1250 in FIG. 12) exerted upon the orientingfeature 540′ will pivot the guide 530″—and thus the matedinstrument—about the landmark.

The guide 530′ and mated instrument 316′ may be rotated, for example,until the orienting indicator 542′ achieves a predetermined signalingrelationship with a landmark 744′ such as the depicted guide pin.Accordingly, the guide 530′ can rotate the instrument 316′ into apredetermined instrument orientation with respect to the glenoid fossa102′ surface.

When at least one landmark 744′ (when present) is a guide pin or otherelongate three-dimensional structure, the guide pin may deflect, ifneeded, to allow the guide 530′ to be lifted longitudinally off theprotruding end guide pin. The guide 530′ may include at least onefrangible portion to allow substantially laterally-oriented removal ofthe guide from around the guide pin or from engagement with theinstrument 316′. As another option, the guide 530′ could include one ormore slots (not shown) to allow removal of the guide by sliding theguide sideways away from the guide pin and/or the instrument 316′. Theabove description presumes that the guide 530 and instrument 316 areremoved from the patient tissue before completion of the surgery. It iscontemplated, nevertheless, that the guide and/or a stock instrumentcomponent could be configured for maintenance of the guide and/orinstrument within the body, perhaps as a part of the completelyinstalled prosthetic implant structure.

It is also contemplated that the guide 530 may be used in conjunctionwith an implant and related structures such as those discussed inco-pending U.S. patent application No. to be determined, filed Oct. 27,2011, titled “System and Method for Assisting with Attachment of a StockImplant to a Patient Tissue” and claiming priority to U.S. ProvisionalPatent Application No. 61/408,324, filed Oct. 29, 2010 and titled“System and Method for Assisting with Attachment of a Stock Implant to aPatient Tissue”, the entire contents of both of which are incorporatedherein by reference.

While aspects of the present invention have been particularly shown anddescribed with reference to the preferred embodiment above, it will beunderstood by those of ordinary skill in the art that various additionalembodiments may be contemplated without departing from the spirit andscope of the present invention. For example, the specific methodsdescribed above for using the guide 530 are merely illustrative; one ofordinary skill in the art could readily determine any number of tools,sequences of steps, or other means/options for placing theabove-described apparatus, or components thereof, into positionssubstantially similar to those shown and described herein. Any of thedescribed structures and components could be integrally formed as asingle piece or made up of separate sub-components, with either of theseformations involving any suitable stock or bespoke components and/or anysuitable material or combinations of materials; however, the chosenmaterial(s) should be biocompatible for most applications of the presentinvention. The mating relationships formed between the describedstructures need not keep the entirety of each of the “mating” surfacesin direct contact with each other but could include spacers or holdawaysfor partial direct contact, a liner or other intermediate member forindirect contact, or could even be approximated with intervening spaceremaining therebetween and no contact. Though certain componentsdescribed herein are shown as having specific geometric shapes, allstructures of the present invention may have any suitable shapes, sizes,configurations, relative relationships, cross-sectional areas, or anyother physical characteristics as desirable for a particular applicationof the present invention. An adhesive (such as, but not limited to, bonecement) could be used in conjunction with the system and methoddescribed herein. The guide 530 may include a plurality of structurescooperatively forming the base body and temporarily or permanentlyattached together in such a manner as to permit relative motion (e.g.,pivoting, sliding, or any other motion) therebetween. Any structures orfeatures described with reference to one embodiment or configuration ofthe present invention could be provided, singly or in combination withother structures or features, to any other embodiment or configuration,as it would be impractical to describe each of the embodiments andconfigurations discussed herein as having all of the options discussedwith respect to all of the other embodiments and configurations. Anadhesive (such as, but not limited to, bone cement) could be used inconjunction with the system and method described herein. Any of thecomponents described herein could have a surface treatment (e.g.,texturization, notching, etc.), material choice, and/or othercharacteristic chosen to provide the component with a desiredinteraction property (e.g., tissue ingrowth, eluting of a therapeuticmaterial, etc.) with the surrounding tissue. A device or methodincorporating any of these features should be understood to fall underthe scope of the present invention as determined based upon the claimsbelow and any equivalents thereof.

Other aspects, objects, and advantages of the present invention can beobtained from a study of the drawings, the disclosure, and the appendedclaims.

1. A guide for assisting with arrangement of a stock instrument withrespect to a patient tissue, the guide comprising: a lower guide surfaceconfigured to contact an upper instrument surface of the stockinstrument when a lower instrument surface of the stock instrument is incontact with the patient tissue, the lower guide surface being contouredto substantially mate with at least a portion of the upper instrumentsurface; an upper guide surface spaced longitudinally apart from thelower guide surface by a guide body, the upper guide surface beingaccessible to a user when the lower guide surface is in contact with theupper instrument surface; and an orienting feature; wherein theorienting feature is configured to enter a predetermined orientingrelationship with a previously placed landmark while the lower guidesurface is in mating contact with at least a portion of the upperinstrument surface in a predetermined relative guide/instrumentorientation, the predetermined orienting relationship indicating thatthe instrument has achieved a predetermined instrument relationship withthe patient tissue.
 2. The guide of claim 1, wherein the stockinstrument includes at least one guide interacting feature, and theguide includes at least one instrument guiding feature at apredetermined feature location with respect to the guide body, at leastone guide interacting feature of the instrument being configured forengagement with at least one instrument guiding feature of the guidewhen the guide and the instrument are in the predetermined relativeguide/instrument orientation.
 3. The guide of claim 1, wherein at leastone previously placed landmark is affixed to the patient tissue at alocation spaced from a location of the stock instrument.
 4. The guide ofclaim 1, wherein a chosen one of the guide interacting feature and theinstrument guiding feature is a protrusion and the other one of theguide interacting feature and the instrument guiding feature is acavity, and the protrusion enters the cavity to engage the guide and theinstrument in the mating contact in the predetermined relativeguide/instrument orientation.
 5. The guide of claim 1, being at leastone of custom-manufactured and modified from a stock guide, responsiveto at least one of preoperative imaging of the patient tissue andpreoperative selection of the stock instrument.
 6. The guide of claim 5,wherein a custom-manufactured orienting feature is provided to a stockguide.
 7. The guide of claim 1, wherein the orienting feature includesan orienting indicator, and the orienting indicator achieves apredetermined signaling relationship with the landmark while the guideand stock instrument are in the predetermined relative guide/instrumentorientation to indicate that the instrument has achieved a predeterminedinstrument relationship with the patient tissue.
 8. The guide of claim1, wherein the stock instrument and the guide are moved concurrently tomove both the guide and stock instrument into predetermined guide andinstrument orientations with respect to the patient tissue.
 9. The guideof claim 1, wherein the stock instrument contains at least one patienttissue modification feature which indicates a predetermined location fora patient tissue modification procedure when the instrument is in thepredetermined instrument orientation with respect to the patient tissue.